Improvement in air-hoists



I i UNITED STATES PATENT Finca.

LEVIS TAXI/'S AND JOHN M. HARTMAN, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNORS TO LOUIS TAIVS AND JOHN M. HARTMAN, OF SAME PLACE.

IMPROVEMENT IN AIR-HOISTS.

Specification forming part of Leiters Patent No. 95.95?, dated October 19, 1869.

To a/ZZ whom it may concern:

Be it known that we, LEWIS Taws and JOHN M. HARTMAN, both of the city and county of Philadelphia, and State of Pennsylvania, have invented a new and Improved Air-Hoist for Blast-Furnaces, Src.; and we do hereby declare that the following is a full, clear, and exact description of thesame, reference being had to the accompanying sheets of drawings, and to the letters of reference marked thereon.

' Our invention consists, first, inthe use and application of one double-acting pneumatic cylinder; second, in effecting an equilibrium between the carrying-platforms and the load on the one part and the piston and the blast on the other part; third, in suspending` the carrying-platforms by means of a balance carrying-ring; fourth, in twisting the strands of one carrying-rope in a contrary direction to that of the other; fifth, in placing the sheavepulleys transversely on the cylinder with respect to a line drawn through the points of suspension of the balance-carrying ring, and of such other devices as are hereinafter shown and described,

On reference to the accompanying sheets of drawings,-making part of this specification, Figure l, Sheet 1, shows an elevation of the air-hoist, viewed from the sides of the platforms. Fig. 2, Sheet 1, is an elevation viewed from the end of the platform. Fig. 3, Sheet l, is a plan view. Fig. 4, Sheet l, shows the method of operating' the three-way cocks for charging and discharging the cylinders. Fig. 5, Sheet 2, is an isometrical view of the cylinder, platforms, &c. Fig. 6, Sheet 2, shows the strands of-the carrying-ropes twisted oppositely. Fig. 7, Sheet 2, shows the ropes when the strands are twisted similarly. Fig. 8, Sheet 2, is a view of the three-way cock 5 and Fig. 9, Sheet 2, is a sectional view of the same.

Similar letters refer to similar parts in the several views. e

A is af double-acting vertical cylinder on a suitable bed-plate.

B is a hollow piston, which is forced alternately up and down in the cylinder A by the alternate admission, to each side, of the blast from' the blowing-engine of the works.

o a are ropes, of wire or other material, prepared with tallow, black lead, and beeswax, I. One end of or other suitable preparation. each is connected to the piston B, while the other ends pass through stufting-boxes d in the l and 5, cast or otherwise xed to the cylin.

inder. The same frami'ngs are employed for both platforms, so that they may have a simultaneous movement. They are composed of the upper and lower parallels, d c, on each side of the cylinder, and extending' both ways beyond it, which are held together and sup ported by the verticals f and the diagonals g, the friction-rollers F being suitably arranged ou transverse shafts L, Fig. 2, to take over the guide rods or tracks G. The hangers N of the platforms, depending from the studs or projections O of the balance-carrying ring, support them. The pawls G are hinged to the lugs or jaws 7L of the balance-carrying ring'D. Their outer ends connect with the ropes a, while their inner ends project downwardly, for vtaking into the teeth of the racks M, which are cast with or otherwise fixed oppositely on the cylinder. Both the pawls andthe racks are equidistant between the points of suspension O of the ring D. If, while operating the hoist, either or both of the ropes a should break, the platforms E would descend by their own weight and gravity, if not arrested bythe springs N on the upper parallels, d, forcing the ends of the pawls into the serrations of the racks. XVe accomplish, as it were, an equilibrium between the platforms and the loads on one hand and the piston and the blast on the other, as follows:

In constructing an air-hoist, it is rst determined the greatest weight the platforms are eX- peeted to raise at any one time. Ordinarily the pressure of the blast is five pounds per square inch of the piston, but sometimes the steam gets very low at a furnace in consequence of there not being sufficient gas generated, then the pressure of the blast on the piston is as low as two or two and a half pounds per square inch. The diameter ofthe piston is, therefore, always calculated for the minimum pressure. If the platforms and loads weigh five hundred pounds each, making one thousand pounds in all, the hollowr piston, -which has been calculated for two hundred and fftypounds7 pressure, must be loaded with pig-iron until it and the pigs weigh seven hundred and iifty pounds, which completes the equilibrium, viz: platforms five hundred pounds-Hoads live hundred poundszone thousand pounds; pressure of blast on the .piston two hundred and fifty pounds-f-piston and pigs seven hundred and fifty poundszone thousand pounds.

It will be observed that the piston descends while the platforms ascend loaded. X'Vhen the piston ascends and the platforms descend unV loaded, the case is the same, for the difference between the ascending piston (seven hundred and fifty pounds) and the unloaded descending platforms (five hundred pounds) is two hundred and fifty pounds, for the blast to eX- ert on the piston, as before. If this equilibrium were not effected, the cylinder would have to be greatlyfenlarged, thereby increasing the volume of the blast used and the working cost of the furnace.

rlhe use of one double-acting cylinder A is entirely new and original. Heretofore singleacting cylinders have been used, but of greatly increased diameter, being unaided by counterbalancing. The increased area of the piston necessitated an increased volume of the blast. Abstracti'ng so much of the blast at a time from the furnace seriously interferes with its proper working. Two double-acting cylinders, the platform being between them, are at present used in air-hoists. The comparisonwith one double-acting cylinder counterbalanced is as follows: Two twenty-four-ineh air-cylinders, double-acting, are incapable of performing more work than one thirty-two-inchdoubleacting air-cylinder counterbalanced. The cost of an air-hoist using two twenty-four-inch cyl-` inders is about sixty-seven hundred dollars, ($6,700.) The cost of an air-hoist using one double-acting cylinder counterbalanc'ed is about forty-three hundred dollars, ($4,800.) There is a very great reduction in the volume of the blast used. It is taken gradually and imperceptibly. The friction is considerably less. As before stated, where two cylinders are used, only one platform is employed, which is` placed between them. If one piston is packed Vtighter than the other, it travels slower, which elevates one side of the platform, and thereby jams it. rlwo double-acting cylinders exhaust such a vast volume of air at one time as to cause a momentarystoppage or ceasing of the smelting. The balance-carry-A to secure by Letters Patent, is-

ing ring D effects an equilibrium between the platforms and the ropes a.. lf one platform or side of the framing should become slightly tightened, the ring will tilt sufficiently to ease it 5 or, if one rope should lengthen more than the other, which is frequently the case, the ring will tilt in that direction and take up the inequality. It was discovered that the ropes a unwound when the pressure of the blast was put on the piston, and caused it to revolve horizontally in the cylinder and the ropes to twist one around the other, as shown in Fig. 7, Sheet 2, and effectually stop .the working of the hoist, to obviate which defect the strands of one rope are twisted in a contrary direction to those of the other, by which they unwind oppositely. The axes c of the sheave-pulleys D are placed above the cylinder, inclined toward a line drawn through-the centers O of suspension of the balance-ringl), so that the vertical plane of a line drawn through the axis of rotation of either shaft'c, will, if produced, meet the vertical plane lof a line drawn through the centers of suspension O of the balance-ring, whereby larger pulleys' are obtained. lIhe friction of the'ropes over the same is vastly reduced. The'ends-of the ropes are attached to the piston atpoints nearer to its periphery, and the-points of'suspension of the ropes with the pawls C of the balance-ring D are at points equidistant vbetween the points of suspension O of the'platforms. The blast is admitted to and discharged from the cylinder A by means of the threeway cocks H on the supply-pipe I, which-connects with the air-pipe J from the blowingcylinder or other. The cocks are for alternately admitting and iiowing off the air from the cylinder, and lto that end are constructed and arranged as shown in Sheet 2, Figs. Sand ,9. The body of the cock has the flanges/'P Q R, for connecting, respectively, with the blastpip'e I and the vcylinder A, and for exhaustingthe cylinder. The plug S of the cock-has its openings z' fi so arranged that the distance between them is greater than the distance-between the ports in the body, so that itmay lap over them. The alternate opening'a'nd closing the cocks simultaneously is effectedby -mea'ns of a T-shaped lever, V, on the upper one, and the straight lever XV on `the lower one, their respective ends being connectedby the ropes 7s, Fig. 4, Sheet l.

'"What 'we claim as our invention, and desire ll. An air-hoist constructed with one doubleacting pneumatic cylinder, substantially as shown.` Y

2. The ropes a, twisted in contrary directions, the hollow piston B, and the cylinder A, substantially as shown and described.

3. The cylinder A, piston B', ropes a, ob-

lique or transverse pulleys D', balance-rig-D, pawls C, and the racks M, substantially/as shown and described.

4.. 'The upper and lower threeway cocks-H H, levers V NV, and `the ropes or rods L', as names to this specieabon in presence of two shown and described. I subscribing witnesses.

5. The cylinder A in combination with the tracks or guides G, rzeks M, platforms E, with IfgETSBEAQISTM ,XN framings, guide-wheels F, balance-ring D, L'

hanger N, pinO, and the paw1s C, substau 'itnesses tially as shown. JOHN CLOUDS,

In testimony whereof We hereunto sign our l HUGH ALEXANDER. 

